As a seat structure, there are those in which, at a seat cushion, the left and right seat side portions are made to be movable to a high position and a low position with respect to a central ceiling plate portion (refer to, for example, Patent Document 1).
In this seat structure, a seat pad within the seat side portion is covered by a seat cover.
However, in this seat structure, when the seat side portions are moved to the low position with respect to the ceiling plate portion, slack arises at the seat cover at the seat cushion end surfaces.                [Patent Document 1] Japanese Patent Application Laid-Open (JP-A) No. 2000-316663        